The invention relates to a method and an apparatus for time-staggered generation of identifying signals by programmable automation components with a system time recorder.
Programmable process controllers having automation components use process data that is read, processed and output periodically or at the time of use. In this system, signals also need to be output on a time-controlled basis using timer modules in the user program or special peripheral modules, which provide a programmable timer module for each time-delayed output signal.
The timer modules in the user program have a relatively large time increment of about one millisecond. The start of time-staggered output of signals or identifying signals is determined in the user program by means of the programming language. After the programmed time has elapsed, response modules in the user program are enabled in which the user can output an identifying signal, such as a switching signal, to the process.
Peripheral units with programmable timer modules are special units that use a hardware-implemented time recorder to provide the time delay for each signal. They are permanently assigned to the signal and can only be used with correspondingly large amounts of design and programming time.
The object of the present invention is to provide a method and device that enable convenient time-staggered generation of identifying signals with minimal hardware complexity. This objective is achieved according to the present invention by assigning an identifying signal to a temporal event by a user, or by an automation component or a by a user program; and registering the event with an event manager with a required event time-delay. The events are sorted chronologically by the event manager, and a system time recorder having a time interval lasting until the next event is started by the event manager. The system time recorder signals when this time interval has elapsed. The event is thus enabled by the event manager, and an identifying signal is thereby generated. Identifying signals can be designed with simplicity and flexibility and changing the assignment of the identifying signals to an event is not complex. Using the event manager, a time recorder can be used advantageously for the generation of more than one different identifying signal.
In a preferred embodiment of the method according to the present invention, at least two system time recorders are used for the generation of identifying signals. Depending on the appearance of the identifying signal, more than one system time recorder or counter can hence be used by the event manager, each of which can also have different time increments.
Another preferred method according to the present invention is checking the availability of the identifying signal for a required event by the user program, or by the signal-specific driver. If the identifying signal is not available at a required point in time, the user program branches into a subprogram or another program section for error handling. By this means, the availability of identifying signals at the required event times is checked. A dual request for an identifying signal at the same instant is thus signaled to the user program and can be avoided by a subsequent error handling procedure.
Yet another preferred method according to the present invention is defining an identifying signal-ON period by an automation component or by a user program; the user program (or the event manager or the signal-specific driver) generates two event input signals at an interval during by the ON period in the event manager. The first signal represents xe2x80x9cStart an actionxe2x80x9d, and the second signal represents xe2x80x9cStop an actionxe2x80x9d. By this means the user can conveniently generate in the event manager an ON period for an identifying signal by means of an automation component or a user program using a program or command call with the ON period as a parameter. It is also conceivable that pre-defined ON periods may be called.
Another preferred aspect of the method according to the present invention is specifying an identifying signal-OFF period instead of the identifying signal ON period. By this means the user can conveniently generate in the event manager an OFF period for an identifying signal by means of an automation component or a user program using a program or command call and the OFF period as a parameter. It is also conceivable that pre-defined OFF periods may be called.
Another preferred feature of the method according to the present invention is to define any identifying signal pattern in a software environment by a user or by a user program; and having the user program (or the event manager or the signal-specific driver) generate in the event manager the event input signals associated with the signal pattern, when the identifying signal pattern is called. By this means any required sequences of identifying signals can be defined and called up by the user via an automation component or via a user program.
A further preferred feature of the method according to the present invention is the defining of periodically recurring ON periods or identifying signal patterns. From the user""s viewpoint, indication that an identifying signal sequence is a periodically recurring pattern simplifies the definition and/or the triggering and/or the storage of periodically recurring identifying signals or identifying signal patterns. It is also optionally possible to define a time interval in the call command during which a periodically recurring identifying signal sequence shall be executed.
Another preferred aspect of the method according to the present invention is where the events of the event manager that have not yet been carried out in time can be corrected. Accordingly, all of the events of the event manager that have not yet been implemented can be edited and if necessary corrected to suit new requirements. For instance a user can define time-staggered identifying signal events which can be confirmed with each polling cycle of the automation component.
Another preferred embodiment of the method according to the present invention is assigning at least one access authorization property to an event; and by utilizing different access authorization properties, different post-processing options are provided for the event or the event data. By assigning access rights, only authorized processes have access to data. For instance a user can define in advance which user, which component or which access process in general has which access rights in the system and is permitted to read and/or change and/or write to the event of the event manager. This also relates to user programs or automation components.
An apparatus in which the method of the present invention may be used includes a user or an automation component or a user program, by which an identifying signal can be assigned to a temporal event; and event manager with which the event can be registered with a required event time-delay. The event manager is capable of chronologically sorting the events. The apparatus also has a system time recorder with a time interval lasting until the next event can be started by the event manager, and the system time recorder/counter can signal when this time interval has elapsed. The event manager can thus enable the event, and thereby cause an identifying signal to be generated. Using such an apparatus one can achieve convenient time-staggered generation of identifying signals with minimum hardware complexity.